Street-canyon pollution with respect to urban-array complexity: The role of lateral and mean pollution fluxes

0489573 - ÚT 2019 RIV NL eng J - Článek v odborném periodiku
Nosek, Štěpán - Fuka, V. - Kukačka, Libor - Kluková, Zuzana - Jaňour, Zbyněk
Street-canyon pollution with respect to urban-array complexity: The role of lateral and mean pollution fluxes.
Building and Environment. Roč. 138, June (2018), s. 221-234. ISSN 0360-1323. E-ISSN 1873-684X
Institucionální podpora: RVO:61388998
Klíčová slova: urban air quality * street canyon * computational modelling * large-eddy simulation * pollution flux * wind-tunnel experiment
Obor OECD: Meteorology and atmospheric sciences
Impakt faktor: 4.820, rok: 2018
https://www.sciencedirect.com/science/article/pii/S0360132318302452

The prediction of pollution within street canyons remains challenging due to the complexity of turbulent flows in urban environments. To improve our understanding of these flows and their relation to the ventilation of street-canyons, we studied pollution fluxes through all street-canyon openings and their balance with respect to urban-array complexity using large-eddy simulations (LES). We validated the LES with wind-tunnel measurements using mean velocities and concentrations and the mean total and turbulent pollution fluxes at the top and lateral openings of the street canyons with either uniform or nonuniform heights and pitched roofs. The LES confirm and extend recent findings about the importance of mean horizontal pollution fluxes for pollutant transport within a street network. The mean fluxes have at least the same dominance as the turbulent ones in case of lateral openings. In case of top openings, the mean fluxes clearly dominate if openings at the roof eaves are selected. While pollutant removal and entrainment through lateral openings are negligible in case of uniform canyons, they are notable in case of nonuniform canyons. We demonstrate that urban roof height nonuniformity does not necessarily enhance the street-canyon ventilation because it worsens (by a factor of 1.1) or improves (by a factor of 1.5) the ventilation compared with the urban uniform height.
Trvalý link: http://hdl.handle.net/11104/0289825